/*
  ==============================================================================

   This file is part of the JUCE framework.
   Copyright (c) Raw Material Software Limited

   JUCE is an open source framework subject to commercial or open source
   licensing.

   By downloading, installing, or using the JUCE framework, or combining the
   JUCE framework with any other source code, object code, content or any other
   copyrightable work, you agree to the terms of the JUCE End User Licence
   Agreement, and all incorporated terms including the JUCE Privacy Policy and
   the JUCE Website Terms of Service, as applicable, which will bind you. If you
   do not agree to the terms of these agreements, we will not license the JUCE
   framework to you, and you must discontinue the installation or download
   process and cease use of the JUCE framework.

   JUCE End User Licence Agreement: https://juce.com/legal/juce-8-licence/
   JUCE Privacy Policy: https://juce.com/juce-privacy-policy
   JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/

   Or:

   You may also use this code under the terms of the AGPLv3:
   https://www.gnu.org/licenses/agpl-3.0.en.html

   THE JUCE FRAMEWORK IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL
   WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING WARRANTY OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

struct Button::CallbackHelper final : public Timer,
                                      public ApplicationCommandManagerListener,
                                      public Value::Listener,
                                      public KeyListener
{
    CallbackHelper (Button& b) : button (b)   {}

    void timerCallback() override
    {
        button.repeatTimerCallback();
    }

    bool keyStateChanged (bool, Component*) override
    {
        return button.keyStateChangedCallback();
    }

    void valueChanged (Value& value) override
    {
        if (value.refersToSameSourceAs (button.isOn))
            button.setToggleState (button.isOn.getValue(), dontSendNotification, sendNotification);
    }

    bool keyPressed (const KeyPress&, Component*) override
    {
        // returning true will avoid forwarding events for keys that we're using as shortcuts
        return button.isShortcutPressed();
    }

    void applicationCommandInvoked (const ApplicationCommandTarget::InvocationInfo& info) override
    {
        if (info.commandID == button.commandID
             && (info.commandFlags & ApplicationCommandInfo::dontTriggerVisualFeedback) == 0)
            button.flashButtonState();
    }

    void applicationCommandListChanged() override
    {
        button.applicationCommandListChangeCallback();
    }

    Button& button;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (CallbackHelper)
};

//==============================================================================
Button::Button (const String& name)  : Component (name), text (name)
{
    callbackHelper.reset (new CallbackHelper (*this));

    setWantsKeyboardFocus (true);
    isOn.addListener (callbackHelper.get());
}

Button::~Button()
{
    clearShortcuts();

    if (commandManagerToUse != nullptr)
        commandManagerToUse->removeListener (callbackHelper.get());

    isOn.removeListener (callbackHelper.get());
    callbackHelper.reset();
}

//==============================================================================
void Button::setButtonText (const String& newText)
{
    if (text != newText)
    {
        text = newText;
        repaint();
    }
}

void Button::setTooltip (const String& newTooltip)
{
    SettableTooltipClient::setTooltip (newTooltip);
    generateTooltip = false;
}

void Button::updateAutomaticTooltip (const ApplicationCommandInfo& info)
{
    if (generateTooltip && commandManagerToUse != nullptr)
    {
        auto tt = info.description.isNotEmpty() ? info.description
                                                : info.shortName;

        for (auto& kp : commandManagerToUse->getKeyMappings()->getKeyPressesAssignedToCommand (commandID))
        {
            auto key = kp.getTextDescription();

            tt << " [";

            if (key.length() == 1)
                tt << TRANS ("shortcut") << ": '" << key << "']";
            else
                tt << key << ']';
        }

        SettableTooltipClient::setTooltip (tt);
    }
}

void Button::setConnectedEdges (int newFlags)
{
    if (connectedEdgeFlags != newFlags)
    {
        connectedEdgeFlags = newFlags;
        repaint();
    }
}

//==============================================================================
void Button::checkToggleableState (bool wasToggleable)
{
    if (isToggleable() != wasToggleable)
        invalidateAccessibilityHandler();
}

void Button::setToggleable (bool isNowToggleable)
{
    const auto wasToggleable = isToggleable();

    canBeToggled = isNowToggleable;
    checkToggleableState (wasToggleable);
}

void Button::setToggleState (bool shouldBeOn, NotificationType notification)
{
    setToggleState (shouldBeOn, notification, notification);
}

void Button::setToggleState (bool shouldBeOn, NotificationType clickNotification, NotificationType stateNotification)
{
    if (shouldBeOn != lastToggleState)
    {
        WeakReference<Component> deletionWatcher (this);

        if (shouldBeOn)
        {
            turnOffOtherButtonsInGroup (clickNotification, stateNotification);

            if (deletionWatcher == nullptr)
                return;
        }

        // This test is done so that if the value is void rather than explicitly set to
        // false, the value won't be changed unless the required value is true.
        if (getToggleState() != shouldBeOn)
        {
            isOn = shouldBeOn;

            if (deletionWatcher == nullptr)
                return;
        }

        lastToggleState = shouldBeOn;
        repaint();

        if (clickNotification != dontSendNotification)
        {
            // async callbacks aren't possible here
            jassert (clickNotification != sendNotificationAsync);

            sendClickMessage (ModifierKeys::currentModifiers);

            if (deletionWatcher == nullptr)
                return;
        }

        if (stateNotification != dontSendNotification)
            sendStateMessage();
        else
            buttonStateChanged();

        if (auto* handler = getAccessibilityHandler())
            handler->notifyAccessibilityEvent (AccessibilityEvent::valueChanged);
    }
}

void Button::setToggleState (bool shouldBeOn, bool sendChange)
{
    setToggleState (shouldBeOn, sendChange ? sendNotification : dontSendNotification);
}

void Button::setClickingTogglesState (bool shouldToggle) noexcept
{
    const auto wasToggleable = isToggleable();

    clickTogglesState = shouldToggle;
    checkToggleableState (wasToggleable);

    // if you've got clickTogglesState turned on, you shouldn't also connect the button
    // up to be a command invoker. Instead, your command handler must flip the state of whatever
    // it is that this button represents, and the button will update its state to reflect this
    // in the applicationCommandListChanged() method.
    jassert (commandManagerToUse == nullptr || ! clickTogglesState);
}

void Button::setRadioGroupId (int newGroupId, NotificationType notification)
{
    if (radioGroupId != newGroupId)
    {
        radioGroupId = newGroupId;

        if (lastToggleState)
            turnOffOtherButtonsInGroup (notification, notification);

        setToggleable (true);
        invalidateAccessibilityHandler();
    }
}

void Button::turnOffOtherButtonsInGroup (NotificationType clickNotification, NotificationType stateNotification)
{
    if (auto* p = getParentComponent())
    {
        if (radioGroupId != 0)
        {
            WeakReference<Component> deletionWatcher (this);

            for (auto* c : p->getChildren())
            {
                if (c != this)
                {
                    if (auto b = dynamic_cast<Button*> (c))
                    {
                        if (b->getRadioGroupId() == radioGroupId)
                        {
                            b->setToggleState (false, clickNotification, stateNotification);

                            if (deletionWatcher == nullptr)
                                return;
                        }
                    }
                }
            }
        }
    }
}

//==============================================================================
void Button::enablementChanged()
{
    updateState();
    repaint();
}

Button::ButtonState Button::updateState()
{
    return updateState (isMouseOver (true), isMouseButtonDown());
}

Button::ButtonState Button::updateState (bool over, bool down)
{
    ButtonState newState = buttonNormal;

    if (isEnabled() && isVisible() && ! isCurrentlyBlockedByAnotherModalComponent())
    {
        if ((down && (over || (triggerOnMouseDown && buttonState == buttonDown))) || isKeyDown)
            newState = buttonDown;
        else if (over)
            newState = buttonOver;
    }

    setState (newState);
    return newState;
}

void Button::setState (ButtonState newState)
{
    if (buttonState != newState)
    {
        buttonState = newState;
        repaint();

        if (buttonState == buttonDown)
        {
            buttonPressTime = Time::getApproximateMillisecondCounter();
            lastRepeatTime = 0;
        }

        sendStateMessage();
    }
}

bool Button::isDown() const noexcept    { return buttonState == buttonDown; }
bool Button::isOver() const noexcept    { return buttonState != buttonNormal; }

void Button::buttonStateChanged() {}

uint32 Button::getMillisecondsSinceButtonDown() const noexcept
{
    auto now = Time::getApproximateMillisecondCounter();
    return now > buttonPressTime ? now - buttonPressTime : 0;
}

void Button::setTriggeredOnMouseDown (bool isTriggeredOnMouseDown) noexcept
{
    triggerOnMouseDown = isTriggeredOnMouseDown;
}

bool Button::getTriggeredOnMouseDown() const noexcept
{
    return triggerOnMouseDown;
}

//==============================================================================
void Button::clicked()
{
}

void Button::clicked (const ModifierKeys&)
{
    clicked();
}

enum { clickMessageId = 0x2f3f4f99 };

void Button::triggerClick()
{
    postCommandMessage (clickMessageId);
}

void Button::internalClickCallback (const ModifierKeys& modifiers)
{
    if (clickTogglesState)
    {
        const bool shouldBeOn = (radioGroupId != 0 || ! lastToggleState);

        if (shouldBeOn != getToggleState())
        {
            setToggleState (shouldBeOn, sendNotification);
            return;
        }
    }

    sendClickMessage (modifiers);
}

void Button::flashButtonState()
{
    if (isEnabled())
    {
        needsToRelease = true;
        setState (buttonDown);
        callbackHelper->startTimer (100);
    }
}

void Button::handleCommandMessage (int commandId)
{
    if (commandId == clickMessageId)
    {
        if (isEnabled())
        {
            flashButtonState();
            internalClickCallback (ModifierKeys::currentModifiers);
        }
    }
    else
    {
        Component::handleCommandMessage (commandId);
    }
}

//==============================================================================
void Button::addListener (Listener* l)      { buttonListeners.add (l); }
void Button::removeListener (Listener* l)   { buttonListeners.remove (l); }

void Button::sendClickMessage (const ModifierKeys& modifiers)
{
    Component::BailOutChecker checker (this);

    if (commandManagerToUse != nullptr && commandID != 0)
    {
        ApplicationCommandTarget::InvocationInfo info (commandID);
        info.invocationMethod = ApplicationCommandTarget::InvocationInfo::fromButton;
        info.originatingComponent = this;

        commandManagerToUse->invoke (info, true);
    }

    clicked (modifiers);

    if (checker.shouldBailOut())
        return;

    buttonListeners.callChecked (checker, [this] (Listener& l) { l.buttonClicked (this); });

    if (checker.shouldBailOut())
        return;

    NullCheckedInvocation::invoke (onClick);
}

void Button::sendStateMessage()
{
    Component::BailOutChecker checker (this);

    buttonStateChanged();

    if (checker.shouldBailOut())
        return;

    buttonListeners.callChecked (checker, [this] (Listener& l) { l.buttonStateChanged (this); });

    if (checker.shouldBailOut())
        return;

    NullCheckedInvocation::invoke (onStateChange);
}

//==============================================================================
void Button::paint (Graphics& g)
{
    if (needsToRelease && isEnabled())
    {
        needsToRelease = false;
        needsRepainting = true;
    }

    paintButton (g, isOver(), isDown());
    lastStatePainted = buttonState;
}

//==============================================================================
void Button::mouseEnter (const MouseEvent&)     { updateState (true,  false); }
void Button::mouseExit (const MouseEvent&)      { updateState (false, false); }

void Button::mouseDown (const MouseEvent& e)
{
    updateState (true, true);

    if (isDown())
    {
        if (autoRepeatDelay >= 0)
            callbackHelper->startTimer (autoRepeatDelay);

        if (triggerOnMouseDown)
            internalClickCallback (e.mods);
    }
}

void Button::mouseUp (const MouseEvent& e)
{
    const auto wasDown = isDown();
    const auto wasOver = isOver();
    updateState (isMouseSourceOver (e), false);

    if (wasDown && wasOver && ! triggerOnMouseDown)
    {
        if (lastStatePainted != buttonDown)
            flashButtonState();

        WeakReference<Component> deletionWatcher (this);

        internalClickCallback (e.mods);

        if (deletionWatcher != nullptr)
            updateState (isMouseSourceOver (e), false);
    }
}

void Button::mouseDrag (const MouseEvent& e)
{
    auto oldState = buttonState;
    updateState (isMouseSourceOver (e), true);

    if (autoRepeatDelay >= 0 && buttonState != oldState && isDown())
        callbackHelper->startTimer (autoRepeatSpeed);
}

bool Button::isMouseSourceOver (const MouseEvent& e)
{
    if (e.source.isTouch() || e.source.isPen())
        return getLocalBounds().toFloat().contains (e.position);

    return isMouseOver();
}

void Button::focusGained (FocusChangeType)
{
    updateState();
    repaint();
}

void Button::focusLost (FocusChangeType)
{
    updateState();
    repaint();
}

void Button::visibilityChanged()
{
    needsToRelease = false;
    updateState();
}

void Button::parentHierarchyChanged()
{
    auto* newKeySource = shortcuts.isEmpty() ? nullptr : getTopLevelComponent();

    if (newKeySource != keySource.get())
    {
        if (keySource != nullptr)
            keySource->removeKeyListener (callbackHelper.get());

        keySource = newKeySource;

        if (keySource != nullptr)
            keySource->addKeyListener (callbackHelper.get());
    }
}

//==============================================================================
void Button::setCommandToTrigger (ApplicationCommandManager* newCommandManager,
                                  CommandID newCommandID, bool generateTip)
{
    commandID = newCommandID;
    generateTooltip = generateTip;

    if (commandManagerToUse != newCommandManager)
    {
        if (commandManagerToUse != nullptr)
            commandManagerToUse->removeListener (callbackHelper.get());

        commandManagerToUse = newCommandManager;

        if (commandManagerToUse != nullptr)
            commandManagerToUse->addListener (callbackHelper.get());

        // if you've got clickTogglesState turned on, you shouldn't also connect the button
        // up to be a command invoker. Instead, your command handler must flip the state of whatever
        // it is that this button represents, and the button will update its state to reflect this
        // in the applicationCommandListChanged() method.
        jassert (commandManagerToUse == nullptr || ! clickTogglesState);
    }

    if (commandManagerToUse != nullptr)
        applicationCommandListChangeCallback();
    else
        setEnabled (true);
}

void Button::applicationCommandListChangeCallback()
{
    if (commandManagerToUse != nullptr)
    {
        ApplicationCommandInfo info (0);

        if (commandManagerToUse->getTargetForCommand (commandID, info) != nullptr)
        {
            updateAutomaticTooltip (info);
            setEnabled ((info.flags & ApplicationCommandInfo::isDisabled) == 0);
            setToggleState ((info.flags & ApplicationCommandInfo::isTicked) != 0, dontSendNotification);
        }
        else
        {
            setEnabled (false);
        }
    }
}

//==============================================================================
void Button::addShortcut (const KeyPress& key)
{
    if (key.isValid())
    {
        jassert (! isRegisteredForShortcut (key));  // already registered!

        shortcuts.add (key);
        parentHierarchyChanged();
    }
}

void Button::clearShortcuts()
{
    shortcuts.clear();
    parentHierarchyChanged();
}

bool Button::isShortcutPressed() const
{
    if (isShowing() && ! isCurrentlyBlockedByAnotherModalComponent())
        for (auto& s : shortcuts)
            if (s.isCurrentlyDown())
                return true;

    return false;
}

bool Button::isRegisteredForShortcut (const KeyPress& key) const
{
    for (auto& s : shortcuts)
        if (key == s)
            return true;

    return false;
}

bool Button::keyStateChangedCallback()
{
    if (! isEnabled())
        return false;

    const bool wasDown = isKeyDown;
    isKeyDown = isShortcutPressed();

    if (autoRepeatDelay >= 0 && (isKeyDown && ! wasDown))
        callbackHelper->startTimer (autoRepeatDelay);

    updateState();

    if (isEnabled() && wasDown && ! isKeyDown)
    {
        internalClickCallback (ModifierKeys::currentModifiers);

        // (return immediately - this button may now have been deleted)
        return true;
    }

    return wasDown || isKeyDown;
}

bool Button::keyPressed (const KeyPress& key)
{
    if (isEnabled() && key.isKeyCode (KeyPress::returnKey))
    {
        triggerClick();
        return true;
    }

    return false;
}

//==============================================================================
void Button::setRepeatSpeed (int initialDelayMillisecs,
                             int repeatMillisecs,
                             int minimumDelayInMillisecs) noexcept
{
    autoRepeatDelay = initialDelayMillisecs;
    autoRepeatSpeed = repeatMillisecs;
    autoRepeatMinimumDelay = jmin (autoRepeatSpeed, minimumDelayInMillisecs);
}

void Button::repeatTimerCallback()
{
    if (needsRepainting)
    {
        callbackHelper->stopTimer();
        updateState();
        needsRepainting = false;
    }
    else if (autoRepeatSpeed > 0 && (isKeyDown || (updateState() == buttonDown)))
    {
        auto repeatSpeed = autoRepeatSpeed;

        if (autoRepeatMinimumDelay >= 0)
        {
            auto timeHeldDown = jmin (1.0, getMillisecondsSinceButtonDown() / 4000.0);
            timeHeldDown *= timeHeldDown;

            repeatSpeed = repeatSpeed + (int) (timeHeldDown * (autoRepeatMinimumDelay - repeatSpeed));
        }

        repeatSpeed = jmax (1, repeatSpeed);

        auto now = Time::getMillisecondCounter();

        // if we've been blocked from repeating often enough, speed up the repeat timer to compensate..
        if (lastRepeatTime != 0 && (int) (now - lastRepeatTime) > repeatSpeed * 2)
            repeatSpeed = jmax (1, repeatSpeed / 2);

        lastRepeatTime = now;
        callbackHelper->startTimer (repeatSpeed);

        internalClickCallback (ModifierKeys::currentModifiers);
    }
    else if (! needsToRelease)
    {
        callbackHelper->stopTimer();
    }
}

std::unique_ptr<AccessibilityHandler> Button::createAccessibilityHandler()
{
    return std::make_unique<detail::ButtonAccessibilityHandler> (*this, AccessibilityRole::button);
}

} // namespace juce